/*
* Copyright © 2008, 2010 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
/**
* \file list.h
* \brief Doubly-linked list abstract container type.
*
* Each doubly-linked list has a sentinel head and tail node. These nodes
* contain no data. The head sentinel can be identified by its \c prev
* pointer being \c NULL. The tail sentinel can be identified by its
* \c next pointer being \c NULL.
*
* A list is empty if either the head sentinel's \c next pointer points to the
* tail sentinel or the tail sentinel's \c prev poiner points to the head
* sentinel.
*
* Instead of tracking two separate \c node structures and a \c list structure
* that points to them, the sentinel nodes are in a single structure. Noting
* that each sentinel node always has one \c NULL pointer, the \c NULL
* pointers occupy the same memory location. In the \c list structure
* contains a the following:
*
* - A \c head pointer that represents the \c next pointer of the
* head sentinel node.
* - A \c tail pointer that represents the \c prev pointer of the head
* sentinel node and the \c next pointer of the tail sentinel node. This
* pointer is \b always \c NULL.
* - A \c tail_prev pointer that represents the \c prev pointer of the
* tail sentinel node.
*
* Therefore, if \c head->next is \c NULL or \c tail_prev->prev is \c NULL,
* the list is empty.
*
* To anyone familiar with "exec lists" on the Amiga, this structure should
* be immediately recognizable. See the following link for the original Amiga
* operating system documentation on the subject.
*
* http://www.natami.net/dev/Libraries_Manual_guide/node02D7.html
*
* \author Ian Romanick <ian.d.romanick@intel.com>
*/
#pragma once
#ifndef LIST_CONTAINER_H
#define LIST_CONTAINER_H
#ifndef __cplusplus
#include <stddef.h>
#endif
#include <assert.h>
#include "ralloc.h"
struct exec_node {
struct exec_node *next;
struct exec_node *prev;
#ifdef __cplusplus
/* Callers of this ralloc-based new need not call delete. It's
* easier to just ralloc_free 'ctx' (or any of its ancestors). */
static void* operator new(size_t size, void *ctx)
{
void *node;
node = ralloc_size(ctx, size);
assert(node != NULL);
return node;
}
/* If the user *does* call delete, that's OK, we will just
* ralloc_free in that case. */
static void operator delete(void *node)
{
ralloc_free(node);
}
exec_node() : next(NULL), prev(NULL)
{
/* empty */
}
const exec_node *get_next() const
{
return next;
}
exec_node *get_next()
{
return next;
}
const exec_node *get_prev() const
{
return prev;
}
exec_node *get_prev()
{
return prev;
}
void remove()
{
next->prev = prev;
prev->next = next;
next = NULL;
prev = NULL;
}
/**
* Link a node with itself
*
* This creates a sort of degenerate list that is occasionally useful.
*/
void self_link()
{
next = this;
prev = this;
}
/**
* Insert a node in the list after the current node
*/
void insert_after(exec_node *after)
{
after->next = this->next;
after->prev = this;
this->next->prev = after;
this->next = after;
}
/**
* Insert a node in the list before the current node
*/
void insert_before(exec_node *before)
{
before->next = this;
before->prev = this->prev;
this->prev->next = before;
this->prev = before;
}
/**
* Insert another list in the list before the current node
*/
void insert_before(struct exec_list *before);
/**
* Replace the current node with the given node.
*/
void replace_with(exec_node *replacement)
{
replacement->prev = this->prev;
replacement->next = this->next;
this->prev->next = replacement;
this->next->prev = replacement;
}
/**
* Is this the sentinel at the tail of the list?
*/
bool is_tail_sentinel() const
{
return this->next == NULL;
}
/**
* Is this the sentinel at the head of the list?
*/
bool is_head_sentinel() const
{
return this->prev == NULL;
}
#endif
};
#ifdef __cplusplus
/* This macro will not work correctly if `t' uses virtual inheritance. If you
* are using virtual inheritance, you deserve a slow and painful death. Enjoy!
*/
#define exec_list_offsetof(t, f, p) \
(((char *) &((t *) p)->f) - ((char *) p))
#else
#define exec_list_offsetof(t, f, p) offsetof(t, f)
#endif
/**
* Get a pointer to the structure containing an exec_node
*
* Given a pointer to an \c exec_node embedded in a structure, get a pointer to
* the containing structure.
*
* \param type Base type of the structure containing the node
* \param node Pointer to the \c exec_node
* \param field Name of the field in \c type that is the embedded \c exec_node
*/
#define exec_node_data(type, node, field) \
((type *) (((char *) node) - exec_list_offsetof(type, field, node)))
#ifdef __cplusplus
struct exec_node;
class iterator {
public:
void next()
{
}
void *get()
{
return NULL;
}
bool has_next() const
{
return false;
}
};
class exec_list_iterator : public iterator {
public:
exec_list_iterator(exec_node *n) : node(n), _next(n->next)
{
/* empty */
}
void next()
{
node = _next;
_next = node->next;
}
void remove()
{
node->remove();
}
exec_node *get()
{
return node;
}
bool has_next() const
{
return _next != NULL;
}
private:
exec_node *node;
exec_node *_next;
};
#define foreach_iter(iter_type, iter, container) \
for (iter_type iter = (container) . iterator(); iter.has_next(); iter.next())
#endif
struct exec_list {
struct exec_node *head;
struct exec_node *tail;
struct exec_node *tail_pred;
#ifdef __cplusplus
/* Callers of this ralloc-based new need not call delete. It's
* easier to just ralloc_free 'ctx' (or any of its ancestors). */
static void* operator new(size_t size, void *ctx)
{
void *node;
node = ralloc_size(ctx, size);
assert(node != NULL);
return node;
}
/* If the user *does* call delete, that's OK, we will just
* ralloc_free in that case. */
static void operator delete(void *node)
{
ralloc_free(node);
}
exec_list()
{
make_empty();
}
void make_empty()
{
head = (exec_node *) & tail;
tail = NULL;
tail_pred = (exec_node *) & head;
}
bool is_empty() const
{
/* There are three ways to test whether a list is empty or not.
*
* - Check to see if the \c head points to the \c tail.
* - Check to see if the \c tail_pred points to the \c head.
* - Check to see if the \c head is the sentinel node by test whether its
* \c next pointer is \c NULL.
*
* The first two methods tend to generate better code on modern systems
* because they save a pointer dereference.
*/
return head == (exec_node *) &tail;
}
const exec_node *get_head() const
{
return !is_empty() ? head : NULL;
}
exec_node *get_head()
{
return !is_empty() ? head : NULL;
}
const exec_node *get_tail() const
{
return !is_empty() ? tail_pred : NULL;
}
exec_node *get_tail()
{
return !is_empty() ? tail_pred : NULL;
}
void push_head(exec_node *n)
{
n->next = head;
n->prev = (exec_node *) &head;
n->next->prev = n;
head = n;
}
void push_tail(exec_node *n)
{
n->next = (exec_node *) &tail;
n->prev = tail_pred;
n->prev->next = n;
tail_pred = n;
}
void push_degenerate_list_at_head(exec_node *n)
{
assert(n->prev->next == n);
n->prev->next = head;
head->prev = n->prev;
n->prev = (exec_node *) &head;
head = n;
}
/**
* Remove the first node from a list and return it
*
* \return
* The first node in the list or \c NULL if the list is empty.
*
* \sa exec_list::get_head
*/
exec_node *pop_head()
{
exec_node *const n = this->get_head();
if (n != NULL)
n->remove();
return n;
}
/**
* Move all of the nodes from this list to the target list
*/
void move_nodes_to(exec_list *target)
{
if (is_empty()) {
target->make_empty();
} else {
target->head = head;
target->tail = NULL;
target->tail_pred = tail_pred;
target->head->prev = (exec_node *) &target->head;
target->tail_pred->next = (exec_node *) &target->tail;
make_empty();
}
}
/**
* Append all nodes from the source list to the target list
*/
void
append_list(exec_list *source)
{
if (source->is_empty())
return;
/* Link the first node of the source with the last node of the target list.
*/
this->tail_pred->next = source->head;
source->head->prev = this->tail_pred;
/* Make the tail of the source list be the tail of the target list.
*/
this->tail_pred = source->tail_pred;
this->tail_pred->next = (exec_node *) &this->tail;
/* Make the source list empty for good measure.
*/
source->make_empty();
}
exec_list_iterator iterator()
{
return exec_list_iterator(head);
}
exec_list_iterator iterator() const
{
return exec_list_iterator((exec_node *) head);
}
#endif
};
#ifdef __cplusplus
inline void exec_node::insert_before(exec_list *before)
{
if (before->is_empty())
return;
before->tail_pred->next = this;
before->head->prev = this->prev;
this->prev->next = before->head;
this->prev = before->tail_pred;
before->make_empty();
}
#endif
/**
* This version is safe even if the current node is removed.
*/
#define foreach_list_safe(__node, __list) \
for (exec_node * __node = (__list)->head, * __next = __node->next \
; __next != NULL \
; __node = __next, __next = __next->next)
#define foreach_list(__node, __list) \
for (exec_node * __node = (__list)->head \
; (__node)->next != NULL \
; (__node) = (__node)->next)
#define foreach_list_const(__node, __list) \
for (const exec_node * __node = (__list)->head \
; (__node)->next != NULL \
; (__node) = (__node)->next)
#define foreach_list_typed(__type, __node, __field, __list) \
for (__type * __node = \
exec_node_data(__type, (__list)->head, __field); \
(__node)->__field.next != NULL; \
(__node) = exec_node_data(__type, (__node)->__field.next, __field))
#define foreach_list_typed_const(__type, __node, __field, __list) \
for (const __type * __node = \
exec_node_data(__type, (__list)->head, __field); \
(__node)->__field.next != NULL; \
(__node) = exec_node_data(__type, (__node)->__field.next, __field))
#endif /* LIST_CONTAINER_H */